This proposal requests NIH support to purchase a VisualSonics Vevo LAZR Photoacoustic and Ultrasound (PA/US) Imaging system. This system is a uniquely integrated imaging system specifically designed for pre-clinical small animal research. This acquisition will reduce the number of animals sacrificed for studies and enable cost-effective, robust longitudinal investigations. The instrument will serve 4 different departments, 16 NIH funded grant projects as major users and 3 projects as minor users spanning a diverse array of topics. It fills a critical need as the existing systems in the Boston area, are not accessible either due to being housed in BL3 facilities, committed to single project use or being located at inconvenient distances. Key applications are listed below, where, by combining photoacoustic and ultrasound technologies into a single, integrated Vevo system, the will provide enhanced capabilities to: Simultaneously capture and present in real time, both physiological and anatomical information of the imaged target Obtain non-invasively high resolution 3D images for treatment planning, of tissue at a depth not obtainable with other optical imaging technologies Measure tissue oxygenation and hemodynamics Longitudinally monitor the physiological and anatomical changes in the same animal The investigators participating in this proposal from MGH's Wellman Center for Photomedicine (Dermatology and Pathology), Martinos Center (Radiology) and Cardiovascluar Research Center (Medicine) represent leading researchers in biomedical research focused on using imaging technology to understand the pathophysiology of a diverse array of high impact diseases such as cancer, cardiovascular disease, abnormal brain function, neurological pathologies and injury, and antibiotic resistant infections, and on translating that insight into clinical practice. Collectivey, these scientists have experience using the most sophisticated optical imaging technologies currently available to biomedical research, each of which has its own intrinsic strengths and weaknesses. As a group, they have determined that the capabilities of the recently commercially available VisualSonics PA/US instrument will complement, currently used systems. It will greatly enhance the quality and productivity of their research.